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Figure 2: Rasch model category probability curves for all items together showing the likelihood that a participant with a particular coping ability will select a category. The scale (xaxis) from +7 to −7 symbolizes the latent trait of healthrelated quality of life, and the yaxis represents the probability of category being selected. Response categories: 0 “abstinence from activity for nonvisual reasons,” 1 “no difficulty with performing activity,” and 5 “severe difficulty with performing activity.” For any given point along this scale, the category most likely to be chosen by a participant is shown by the category curve with the highest probability 
